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比较了陕北沙地沙柳、柠条和沙棘3种典型灌木不同土壤深度(0~20和30~50 cm)根木质部解剖结构和水力特性.结果表明:沙柳具有较高的叶水势,根木质部导管平均最大直径(dmax)、平均最小直径(dmin)、平均导管面积(Alum)以及导管面积占木质部面积比例(Aves/Axyl)显著高于柠条和沙棘,根导管密度(VD)与沙棘相当但显著高于柠条;沙柳根的比导水率分别为柠条和沙棘的5.0和2.8倍;沙柳根栓塞脆弱性指数与柠条根相当,但显著高于沙棘根.表明沙柳属耗水型水分利用策略,而柠条和沙棘属节水型水分利用策略,且柠条更耐旱.3种灌木在2个土层深度的dmax、dmin和Alum无显著差异,但30~50 cm土层根VD和Aves/Axyl显著高于表层;30~50 cm土层根比导水率显著高于表层根,但脆弱性指数小于表层根,深层根具有高的水分传输效率和低的水力脆弱性.
The anatomical structure and hydraulic characteristics of xylem at different depths (0 ~ 20 and 30 ~ 50 cm) of Salix psammophila, Caragana korshinskii and Seabuckthorn in sandy soil of northern Shaanxi were compared.The results showed that Salix psammophila had higher leaf water potential, Root mean diameter (dmax), mean minimum diameter (dmin), average lumen area (Alum), and catheter area to lumber area ratio (Aves / Axyl) were significantly higher than those of Caragana korshinskii and Seabuckthorn. Root canal density Seabuckthorn was significantly but significantly higher than that of Caragana korshinskii. The specific hydraulic conductivity of Salix psammophila was 5.0 and 2.8 times higher than that of Caragana korshinskii and Seabuckthorn respectively. The index of fragility of Salix root was similar to that of Caragana korshinskii, but significantly higher than that of Seabuckthorn Is a water-saving water use strategy, while the Caragana korshinskii and Seabuckthorn are water-saving water use strategies, and the Caragana korshinskii is more drought-resistant.The dmax, dmin and Alum of the three shrubs in the two soil depths showed no significant difference, The root VD and Aves / Axyl of 50 cm soil layer were significantly higher than those of the surface layer. The root canal specific hydraulic conductivity of 30-50 cm soil layer was significantly higher than that of the surface root, but the vulnerability index was less than that of the surface root. The deep roots had high water transfer efficiency and low The hydraulic vulnerability.